This invention relates to conveying blanks or articles having magnetic properties exiting from a press or a shear, and automatically and neatly piling them in a stacking station. It is particularly suited for use with either flat blanks or stamped blanks with a regular or irregular shape.
It will be appreciated that the invention has a wide general use to handling various kinds and shapes of articles such as body parts having magnetic properties and used in the automotive industry; however for purposes herein, it will be discussed as generally applied to handling metal blanks which may be shaped by stamping for such industry, which stamping is done by a press.
Press feed line arrangements for stacking metal parts have been developed heretofore. These arrangements include a catching conveyor disposed immediately adjacent to the exit of the press and an overhead magnetic conveyor for receiving the blanks from the line and dropping the same in a piling or stacking station, where they come to rest in stacked relation on a pallet supported by a stacker car from whence the stack with the pallet is readily removed and sent downstream along the feed line for further processing operations or storage. Some of the background for the present invention can be found in U.S. Pat. Nos. 2,374,174; 3,020,810; and 3,369,806 issuing to Buccione.
While such arrangements for slow speed operation and for heavy gauge, flat regular shaped stock have proven to a degree to be successful, they have been found to be unacceptable for present-day more stringent requirements where the speeds are substantially higher, the gauges are substantially thicker, and the blanks take many different sizes, contours, and shapes, and their tolerances for surface scratching has been substantially decreased.
In known systems, when a blank exiting the press after the pressing operation is large and extends beyond the press, it is supported by a catching conveyor prior to its being severed from the parent material. This catching conveyor generally cannot be stopped and started with the receiving of successive blanks since the exit speed of the blanks including the acceleration rate for the conveyor are too high to drive the belts of the catching conveyor in a practical manner. Also, since this catching conveyor cannot be operated at the same rate of speed as the speed of the exiting blank, invariably damage or scratching to the blank occurs.
Some of these adverse conditions also occur in handling short blanks which must be quickly decelerated because of space requirements, and yet the deceleration and stoppage must be controlled to avoid an ojectionable markings.
It is, therefore, an object of the present invention to provide in an arrangement for a press feed line, a means and method for handling blanks exiting the press at high rates of speed in a manner that the speed upon their exit is decelerated in a controlled manner so that each blank is allowed to safely drop onto a catching conveyor thereby resisting any scratching or damaging of the blank.
More particularly, a magnetic conveyor unit is provided immediately adjacent to the exit side of the press for picking up the blank and then conveying it to a catching conveyor. The magnetic conveyor unit comprises a plurality of anti-frictional, low inertial, non-driven rollers and an array of electromagnets located inwardly of the rollers such that the electromagnets pick up the blank, with only the surface of the rollers coming into direct contact with the blank. The rollers and electromagnets are mounted on a plurality of rail or carrier assemblies which are individually operated and adjusted to conform to the face of the die in the press for optimum support of the blank.
From the catching conveyor the blanks must then be neatly and automatically stacked with minimum side variations, with the center of the blank being aligned with the center of the pallet on a stacker car. Also, it is desirable to position the pallet on the stacker car prior to the pallet's removal therefrom so that the center of the stacked blanks is such that the stack can be easily received and handled by equipment downstream of the press area.
It is a further object of the present invention to provide means which lends the stacking process to robotic treatment which neatly forms the stacks, and maintains the neatly formed stacks on the pallet. This is especially important in the instance where the blanks take many different shapes, some of which are small, polymorphic shapes. A specially designed stacker car aids in this stacking process and permits different positioning of the pallet in the stacking station.
Depending on the type of press and the design of the die therein, blanks may be discharged from the top and/or bottom surfaces of the die.
It is a still further object of the present invention to provide an arrangement in a press feed line for receiving a blank from two different locations or sources in the press either at the same time servicing several stacking stations, or at different time intervals servicing alternate stacking stations.
In a broad application, it is a further object of the present invention to provide an arrangement in a press feed line for handling blanks, that can be fully automated and computer controlled to handle and stack blanks of a large range of sizes and shapes at optimum speeds, ease, and efficiency.